fa69d08d13
libmisc/xgetpwuid.c, libmisc/xgetgrgid.c, libmisc/xgetspnam.c: Do not limit the size of the buffer to hold the group or user structure. It used to be limited to 16k, which caused issues with groups having many users.
145 lines
4.5 KiB
C
145 lines
4.5 KiB
C
/*
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* Copyright (c) 2007 - 2009, Nicolas François
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the copyright holders or contributors may not be used to
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* endorse or promote products derived from this software without
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* specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
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* PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* According to the Linux-PAM documentation:
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*
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* 4.1. Care about standard library calls
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*
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* In general, writers of authorization-granting applications should
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* assume that each module is likely to call any or all 'libc' functions.
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* For 'libc' functions that return pointers to static/dynamically
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* allocated structures (ie. the library allocates the memory and the
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* user is not expected to 'free()' it) any module call to this function
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* is likely to corrupt a pointer previously obtained by the application.
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* The application programmer should either re-call such a 'libc'
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* function after a call to the Linux-PAM library, or copy the structure
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* contents to some safe area of memory before passing control to the
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* Linux-PAM library.
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*
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* Two important function classes that fall into this category are
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* getpwnam(3) and syslog(3).
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*
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* This file provide wrapper to the getpwnam or getpwnam_r functions.
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*/
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#include <unistd.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <errno.h>
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#include "prototypes.h"
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#define XFUNCTION_NAME XPREFIX (FUNCTION_NAME)
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#define XPREFIX(name) XPREFIX1 (name)
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#define XPREFIX1(name) x##name
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#define REENTRANT_NAME APPEND_R (FUNCTION_NAME)
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#define APPEND_R(name) APPEND_R1 (name)
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#define APPEND_R1(name) name##_r
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#define STRINGIZE(name) STRINGIZE1 (name)
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#define STRINGIZE1(name) #name
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/*@null@*/ /*@only@*/LOOKUP_TYPE *XFUNCTION_NAME (ARG_TYPE ARG_NAME)
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{
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#if HAVE_FUNCTION_R
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LOOKUP_TYPE *result=NULL;
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char *buffer=NULL;
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/* we have to start with something */
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size_t length = 0x100;
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result = malloc(sizeof(LOOKUP_TYPE));
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if (NULL == result) {
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fprintf (stderr, _("%s: out of memory\n"),
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"x" STRINGIZE(FUNCTION_NAME));
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exit (13);
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}
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while (true) {
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int status;
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LOOKUP_TYPE *resbuf = NULL;
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buffer = (char *)realloc (buffer, length);
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if (NULL == buffer) {
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fprintf (stderr, _("%s: out of memory\n"),
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"x" STRINGIZE(FUNCTION_NAME));
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exit (13);
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}
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errno = 0;
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status = REENTRANT_NAME(ARG_NAME, result, buffer,
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length, &resbuf);
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if ((0 ==status) && (resbuf == result)) {
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/* Build a result structure that can be freed by
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* the shadow *_free functions. */
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LOOKUP_TYPE *ret_result = DUP_FUNCTION(result);
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free(buffer);
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free(result);
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return ret_result;
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}
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if (ERANGE != errno) {
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free (buffer);
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free (result);
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return NULL;
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}
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if (length <= ((size_t)-1 / 4)) {
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length *= 4;
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} else if (length == (size_t) -1) {
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break;
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} else {
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length = (size_t) -1;
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}
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}
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free(buffer);
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free(result);
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return NULL;
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#else /* !HAVE_FUNCTION_R */
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/* No reentrant function.
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* Duplicate the structure to avoid other call to overwrite it.
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*
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* We should also restore the initial structure. But that would be
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* overkill.
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*/
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LOOKUP_TYPE *result = FUNCTION_NAME(ARG_NAME);
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if (result) {
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result = DUP_FUNCTION(result);
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if (NULL == result) {
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fprintf (stderr, _("%s: out of memory\n"),
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"x" STRINGIZE(FUNCTION_NAME));
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exit (13);
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}
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}
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return result;
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#endif
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}
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